Here's why it might seem like a suffix:
* It's often attached to other words: You see "liter" added to words like "milliliter" (mL) and "kiloliter" (kL).
* It represents a specific quantity: Just like "meter" for length, "liter" signifies a certain amount of space occupied by a substance.
So, "liter" itself doesn't have a meaning, but it's a crucial component in understanding units of volume.